Module api_mcp 

/api/mcp/* — discovery + health proxy for the in-process MCP server.

The MCP server now runs as a tokio task inside the main construct daemon (see gateway::run_gateway), not as a separate construct-mcp process. It binds an ephemeral port and writes the real URL to ~/.construct/mcp.json; the frontend reads that instead of hardcoding a port.

This module exposes GET /api/mcp/discovery which:

1. Reads the discovery file (mtime-cached).
2. Issues a short-timeout GET <url>/health against the MCP server.
3. Returns a uniform JSON shape the UI can use to drive the status badge.

Structs

ReqwestHealthProbe

Default reqwest-backed probe with a 500ms timeout.

TestServerRequest

Wire shape posted by ConfigV2’s McpServerEntry — tolerant of unset fields for the transport the user didn’t select. We translate to McpServerConfig before handing off to the existing client.

Traits

HealthProbe

Health probe interface — trivially mockable in tests.

Functions

build_discovery_payload

Core decision logic, factored so tests can inject fakes.

handle_api_mcp_call

POST /api/mcp/call — proxy to the MCP server’s POST /mcp (JSON-RPC 2.0).

handle_api_mcp_discovery

GET /api/mcp/discovery

handle_api_mcp_health

GET /api/mcp/health — direct proxy to the MCP server’s /health endpoint (convenience for the UI). Not required for session setup.

handle_api_mcp_servers_test

POST /api/mcp/servers/test

handle_api_mcp_session_create

POST /api/mcp/session — proxy to the MCP server’s POST /session.

handle_api_mcp_session_events

GET /api/mcp/session/{id}/events — SSE passthrough.

request_to_config

Validate the request and build an McpServerConfig ready to connect.